Tech-invite 3GPPspace IETFspace

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Content for TR 29.806 Word version: 12.1.0

1… 2…

2 References p. 7

3 Abbreviations p. 7

4 Existing restoration procedures p. 8

4.1 Introduction p. 8

4.1.1 Stage 2 description of existing restoration procedures p. 8

4.1.1.1 Specified mechanisms p. 8

4.1.1.2 "Update PDP context/Bearer at P-CSCF failure" mechanism p. 9

4.1.2 Stage 3 description of existing restoration procedures and P-CSCF discovery p. 9

4.1.2.1 Introduction p. 9

4.1.2.2 3GPP accesses p. 10

4.1.2.2.1 GPRS p. 10

4.1.2.2.2 E-UTRAN p. 10

4.1.2.3 Non-3GPP accesses p. 10

4.1.2.3.1 WLAN p. 10

4.1.2.3.2 Fixed broadband connection p. 11

4.1.2.3.3 Data Over Cable Service Interface Specification (DOCSIS) p. 11

4.1.2.3.4 Cdma2000 packet data subsystem p. 11

4.1.2.3.5 EPC via Cdma2000 High Rate Packet Data (HRPD) p. 11

4.1.2.3.6 WLAN using EPC p. 12

4.1.2.3.7 Digital Video Broadcasting - Return Channel via Satellite (DVB-RCS2) p. 12

4.1.3 GSMA specifications related to P-CSCF restoration p. 12

4.2 Limitations and drawbacks p. 13

4.2.1 Limitations of "Update PDP context/Bearer at P-CSCF failure" p. 13

4.2.2 Limitations of "Inform UE about P-CSCF failure" p. 13

4.2.3 Limitations and criteria comparison of "UE using keep-alive" p. 14

4.2.3.1 Limitations p. 14

4.2.3.2 Criteria analysis p. 14

5 Objectives p. 15

6 Solution alternatives p. 16

6.1 Introduction p. 16

6.2 Sol-A: Double IMS registration p. 16

6.2.1 Overview p. 16

6.2.2 Principles p. 16

6.2.3 Description p. 16

6.2.3.1 Detection of the P-CSCF failure p. 16

6.2.3.2 Registration p. 17

6.2.3.3 New originating sessions: p. 17

6.2.3.4 New terminating sessions p. 17

6.2.4 Coexistence with existing solution p. 17

6.2.5 Objective compliance p. 18

6.3 Sol-B: Alternative P-CSCF and PCRF based restoration p. 18

6.3.1 Overview p. 18

6.3.2 Principles p. 19

6.3.3 Description p. 19

6.3.3.1 Procedures p. 19

6.3.3.2 Optional functions p. 24

6.3.3.2.1 SIP level keep-alive function p. 24

6.3.3.2.2 Dynamic alternative P-CSCF configuration at adjacent node p. 24

6.3.3.2.3 Indication of UE supporting the PCO based P-CSCF restoration p. 25

6.3.3.2.3.1 Introduction p. 25

6.3.3.2.3.2 Option 1 - IMS Registration based Indication p. 25

6.3.3.2.3.3 Option 2 - PCO based Indication p. 25

6.3.4 Coexistence with existing solution p. 25

6.3.5 Objective compliance p. 25

6.3.6 Solution B Roaming considerations p. 26

6.4 Sol-C: Alternative with AS (via ISC and Sh) p. 26

6.4.1 Overview p. 26

6.4.2 Principles p. 26

6.4.3 Description p. 27

6.4.3.1 Procedures p. 27

6.4.3.2 S-CSCF/AS detection p. 29

6.4.3.2.1 General p. 29

6.4.3.2.2 S-CSCF adjacent SIP node to P-CSCF p. 30

6.4.3.2.3 S-CSCF not adjacent SIP node to P-CSCF p. 31

6.4.3.2.4 The originating user cancels the call p. 31

6.4.4 Coexistence with existing solution p. 31

6.4.5 Objective compliance p. 31

6.5 Sol-D: Alternative with direct Cx communication p. 32

6.5.1 Overview p. 32

6.5.2 Principles p. 33

6.5.3 Description p. 33

6.5.3.1 Procedures p. 33

6.5.3.2 Reuse of Rel-9 PCO based P-CSCF Restoration procedures p. 34

6.5.3.2.1 Introduction p. 34

6.5.3.2.2 Extension 1 - Decision at MME/SGSN p. 34

6.5.3.2.2.1 Extension 1 - Procedure description p. 34

6.5.3.2.2.2 Methods to indicate the UE's support for Rel-9 PCO based P-CSCF Restoration to MME/SGSN p. 37

6.5.3.2.2.2.1 Method 1 - NAS based p. 37

6.5.3.2.2.2.2 Method 2 - IMS registration based p. 37

6.5.3.2.3 Extension 2 - Decision at P-GW/GGSN p. 38

6.5.3.2.3.1 Extension 2 - Procedure description p. 38

6.5.3.2.3.2 Method to indicate the UE support for Rel-9 PCO based P-CSCF Restoration to PGW/GGSN p. 40

6.5.4 Coexistence with existing solution p. 40

6.5.5 Objective compliance p. 40

6.5.6 Roaming considerations p. 41

6.5.6.1 Introduction p. 41

6.5.6.2 Rel-9 P-CSCF Restoration for roamers only when HPLMN does not support the HSS based mechanism p. 41

6.5.6.3 Rel-9 P-CSCF Restoration always for roamers p. 41

6.5.6.4 No P-CSCF Restoration mechanism for roamers when HPLMN does not support the HSS based mechanism p. 41

6.5.6.5 Conclusions p. 41

6.5.7 Solutions B and D commonalities p. 42

6.5.7.1 Basic mechanism p. 42

6.5.7.2 Optional extension p. 42

6.5.7.3 Conclusions on Solutions B and D Commonalities p. 42

6.6 P-CSCF restart case p. 43

6.6.1 Introduction p. 43

6.6.2 Considerations regarding a restarted P-CSCF p. 43

6.6.3 Solutions addressing P-CSCF restart p. 43

6.6.3.1 Solution with a new indicator p. 43

6.6.3.2 Solution without a new indicator p. 44

6.6.4 Comparison of solutions for P-CSCF restart p. 44

6.6.5 Recommendation on P-CSCF restart p. 44

7 Conclusions p. 45

7.1 Comparison analysis p. 45

7.1.1 Comparison criteria p. 45

7.1.2 Sol-A: Double IMS registration p. 46

7.1.3 Sol-C: Alternative with AS (via ISC and Sh) p. 46

7.1.4 Sol-D: Alternative with direct Cx communication p. 48

7.1.4.1 Basic mechanism - PDN disconnection p. 48

7.1.4.2 Reuse of Rel-9 PCO based P-CSCF Restoration procedures extensions p. 49

7.1.4.2.1 Extension 1 - Decision at MME/SGSN p. 49

7.1.4.2.1.1 Extension 1 Comparison criteria p. 49

7.1.4.2.1.2 Methods to indicate the UE's support for Rel-9 PCO based P-CSCF Restoration procedures to MME/SGSN p. 50

7.1.4.2.1.2.1 Introduction p. 50

7.1.4.2.1.2.2 Method 1 - NAS based p. 50

7.1.4.2.1.2.3 Method 2 - IMS registration based p. 51

7.1.4.2.2 Extension 2 - Decision at P-GW/GGSN p. 51

7.1.4.2.2.1 Extension 2 - Comparison criteria p. 51

7.1.4.2.2.2 Method to indicate the UE's support for Rel-9 PCO based P-CSCF Restoration procedures to P-GW/GGSN p. 52

7.1.4.2.3 Optional extensions comparison and selection p. 53

7.1.4.2.3.1 Introduction p. 53

7.1.4.2.3.2 NAS based p. 53

7.1.4.2.3.3 IMS registration based p. 53

7.1.4.2.3.4 PCO based p. 53

7.1.4.2.3.5 Selection p. 54

7.1.5 Sol-B: Alternative P-CSCF and PCRF based restoration p. 54

7.1.5.1 Introduction p. 54

7.1.5.2 Basic mechanism - PDN disconnection p. 54

7.1.5.3 Extension - Reuse of Rel-9 PCO based P-CSCF restoration p. 55

7.1.5.3.1 General p. 55

7.2 Final conclusion p. 56

A Solution D extension for non-3GPP access p. 58

$ Change History p. 61